4 Newton's Laws of Motion - BC Science Physics 11

Part 2: Motion from Rest
Figure 4.3.3 Set-up for part 2
1. Place a piece of light plastic insulating Styrofoam board (50 cm × 25 cm × 2.5 cm) at one end of an air table as
shown in Figure 4.3.3. Place a wind-up toy car or a radio-controlled car at one end of the board. Turn on the air
table and start the car moving. Observe and describe what happens:
(a) to the car
(b) to the “road” under the car
2. How does this demonstration illustrate Newton’s Third Law?
Part 3: Tug of War
Figure 4.3.4 Students stretching the string
1. Tie a string between two 20 N spring balances. Have two students stretch the string between them as shown in
Figure 4.3.4. What do the two spring balances read?
2. Try pulling with different forces. Compare the forces on each spring balance each time you pull on the string
with a different force. Does it matter who does the pulling?
3. Try adding a third spring balance in the middle of the string. How does this demonstration illustrate Newton’s
third law?
Concluding Questions
1. When a car moves forward, in which direction do the wheels of the car push on the road? What force actually
makes the car move forward?
2. List and discuss three examples of situations from your own everyday experience, that involve Newton’s third
law.
© Edvantage Interactive 2012 ISBN 978-0-9864778-3-6 Chapter 4 Newton’s Laws of Motion 119